[horde] Problem of slow with server-side sorting

[Jose Luis Marin Perez]

Thank you very much for your replies. 

I am clear that the problem of slowness is caused by Courier-Imap. 

 There are ways to migrate from Courier-IMAP to Cyrus without losing information of the accounts? 

There is a high risk of doing so? 

 Thanks

Jolumape

> Date: Tue, 2 Jun 2009 09:15:54 -0700
> From: morgan at orst.edu
> To: vilius at lnk.lt
> CC: horde at lists.horde.org
> Subject: Re: [horde] Problem of slow with server-side sorting
> 
> On Tue, 2 Jun 2009, Vilius Šumskas wrote:
> 
> >> I thank you all for your reply.
> >>
> >>  Could configure "Arrival Time"
> >> in the accounts, but I like to go deeper into the solution of this
> >> problem, know the real cause of the slow, perhaps because the server
> >> hardware, the courier-imap, etc..
> >>
> >>  We would appreciate if you could help me because the problems are
> >> becoming massive.
> >
> > I *think* the root cause is Courier IMAP, because as I told you earlier it
> > doesn't handle large mailboxes well. Why is it so I'm not sure. Maybe it is
> > related to internal Courier caching during expensive operations. All I know
> > that slowness was the main reason why we moved to Cyrus.
> 
> Courier is slow on large mailboxes because it uses the "maildir" format 
> for storing email.  In this format, each message is a separate file.  When 
> you ask the server to sort by something other than arrival time, it must 
> open each message file to read the message headers.  As you can imagine, 
> it takes a long time to open several thousand files and read their 
> contents.
> 
> > I just did quick test on a Cyrus mailbox with 7700+ messages on the machine
> > with Operator processor, 2GB of RAM and SATA RAID5 array. It took less than
> > 3 seconds.
> 
> Cyrus improves on maildir by also creating additional files in each 
> directory named cyrus.index and cyrus.cache.  These files contain the 
> message headers so that Cyrus can quickly retrieve the headers from a 
> single file.
> 
>  	Andy

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